#!/bin/sh

# set -e

export PATH=/root/usr/bin:/root/usr/sbin:/root/bin:/root/sbin:/usr/bin:/usr/sbin:/bin:/sbin

echo "/root/lib" >> /etc/ld.so.conf
echo "/root/usr/lib" >> /etc/ld.so.conf

mountpoint=/cdrom

root_persistence="casper-rw"
home_persistence="casper-rw"
root_snapshot_label="casper-sn"
home_snapshot_label="home-sn"

USERNAME=ubuntu
USERFULLNAME="A Exam Student using Digeks"
HOST=live
BUILD_SYSTEM=Ubuntu

mkdir -p $mountpoint

[ -f /etc/casper.conf ] && . /etc/casper.conf
export USERNAME USERFULLNAME HOST BUILD_SYSTEM

. /scripts/casper-helpers

if [ ! -f /casper.vars ]; then
    touch /casper.vars
fi

parse_cmdline() {
    for x in $(cat /proc/cmdline); do
        case $x in
            persistent)
                export PERSISTENT="Yes" ;;
            nopersistent)
                export PERSISTENT="" ;;
            union=*)
                export UNIONFS="${x#union=}";;
            ip*)
                STATICIP=${x#ip=}
                if [ "${STATICIP}" = "" ]; then
                    STATICIP="frommedia"
                fi
                export STATICIP ;;
            ignore_uuid)
                IGNORE_UUID="Yes" ;;
        esac
    done
    if [ "${UNIONFS}" = "" ]; then
        export UNIONFS="unionfs"
    fi
}

is_casper_path() {
    path=$1
    if [ -d "$path/casper" ]; then
        if [ "$(echo $path/casper/*.squashfs)" != "$path/casper/*.squashfs" ] ||
            [ "$(echo $path/casper/*.ext2)" != "$path/casper/*.ext2" ] ||
            [ "$(echo $path/casper/*.dir)" != "$path/casper/*.dir" ]; then
            return 0
        fi
    fi
    return 1
}

matches_uuid() {
    if [ "$IGNORE_UUID" ] || [ ! -e /conf/uuid.conf ]; then
        return 0
    fi
    path="$1"
    uuid="$(cat /conf/uuid.conf)"
    for try_uuid_file in "$mountpoint/.disk/casper-uuid"*; do
        [ -e "$try_uuid_file" ] || continue
        try_uuid="$(cat "$try_uuid_file")"
        if [ "$uuid" = "$try_uuid" ]; then
            return 0
        fi
    done
    return 1
}

get_backing_device() {
    case "$1" in
        *.squashfs|*.ext2)
            echo $(setup_loop "$1" "loop" "/sys/block/loop*")
            ;;
        *.dir)
            echo "directory"
            ;;
        *)
            panic "Unrecognized casper filesystem: $1"
            ;;
    esac
}

match_files_in_dir() {
    # Does any files match pattern $1 ?

    local pattern="$1"
    if [ "$(echo $pattern)" != "$pattern" ]; then
        return 0
    fi
    return 1
}

mount_images_in_directory() {
    directory="$1"
    rootmnt="$2"
    if match_files_in_dir "$directory/casper/*.squashfs" ||
        match_files_in_dir "$directory/casper/*.ext2" ||
        match_files_in_dir "$directory/casper/*.dir"; then
        setup_unionfs "$directory/casper" "$rootmnt"
    else
        :
    fi
}

is_nice_device() {
    sysfs_path="${1#/sys}"
    if /lib/udev/path_id "${sysfs_path}" | grep -E -q "ID_PATH=(usb|pci-[^-]*-[ide|scsi|usb])"; then
        return 0
    fi
    return 1
}

is_supported_fs () {
    # FIXME: do something better like the scan of supported filesystems
    fstype="${1}"
    case ${fstype} in
        vfat|iso9660|udf|ext2|ext3|ntfs)
            return 0
            ;;
    esac
    return 1
}

copy_live_to() {
    copyfrom="${1}"
    copytodev="${2}"
    copyto="${copyfrom}_swap"

    size=$(fs_size "" ${copyfrom} "used")

    if [ "${copytodev}" = "ram" ]; then
        # copying to ram:
        freespace=$( expr $(awk '/MemFree/{print $2}' /proc/meminfo) + $( cat /proc/meminfo | grep Cached | head -n 1 | awk '/Cached/{print $2}' - ) )
        mount_options="-o size=${size}k"
        free_string="memory"
        fstype="tmpfs"
        dev="/dev/shm"
    else
        # it should be a writable block device
        if [ -b "${copytodev}" ]; then
            dev="${copytodev}"
            free_string="space"
            fstype=$(get_fstype "${dev}")
            freespace=$(fs_size "${dev}")
        else
            [ "$quiet" != "y" ] && log_warning_msg "${copytodev} is not a block device."
            return 1
        fi
    fi
    if [ "${freespace}" -lt "${size}" ] ; then
        [ "$quiet" != "y" ] && log_warning_msg "Not enough free ${free_string} (${freespace}k > ${size}k) to copy live media in ${copytodev}."
        return 1
    fi

    # begin copying..
    mkdir "${copyto}"
    echo "mount -t ${fstype} ${mount_options} ${dev} ${copyto}"
    mount -t "${fstype}" ${mount_options} "${dev}" "${copyto}"
    cp -a ${copyfrom}/* ${copyto} # "cp -a" from busybox also copies hidden files
    umount ${copyfrom}
    mount -r -o move ${copyto} ${copyfrom}
    rmdir ${copyto}
    return 0
}

do_netmount() {
    rc=1

    modprobe "${MP_QUIET}" af_packet # For DHCP

    /sbin/udevadm trigger
    /sbin/udevadm settle

    ipconfig ${DEVICE} /tmp/net-${DEVICE}.conf | tee /netboot.config

    if [ "${NFSROOT}" = "auto" ]; then
        NFSROOT=${ROOTSERVER}:${ROOTPATH}
    fi

    [ "$quiet" != "y" ] && log_begin_msg "Trying netboot from ${NFSROOT}"

    if [ "${NETBOOT}" != "nfs" ] && do_cifsmount ; then
        rc=0
    elif do_nfsmount ; then
        NETBOOT="nfs"
        export NETBOOT
        rc=0
    fi

    [ "$quiet" != "y" ] && log_end_msg
    return ${rc}
}

do_nfsmount() {
    rc=1
    modprobe "${MP_QUIET}" nfs
    if [ -z "${NFSOPTS}" ]; then
        NFSOPTS=""
    fi

    [ "$quiet" != "y" ] && log_begin_msg "Trying nfsmount -o nolock -o ro ${NFSOPTS} ${NFSROOT} ${mountpoint}"
    # FIXME: This for loop is an ugly HACK round an nfs bug
    for i in 0 1 2 3 4 5 6 7 8 9 a b c d e f 10 11 12 13; do
        nfsmount -o nolock -o ro ${NFSOPTS} "${NFSROOT}" "${mountpoint}" && rc=0 && break
        sleep 1
    done
    return ${rc}
}

do_cifsmount() {
    rc=1
    if [ -x "/sbin/mount.cifs" ]; then
        if [ -z "${NFSOPTS}" ]; then
            CIFSOPTS="-ouser=root,password="
        else
            CIFSOPTS="${NFSOPTS}"
        fi

        [ "$quiet" != "y" ] && log_begin_msg "Trying mount.cifs ${NFSROOT} ${mountpoint} ${CIFSOPTS}"
        modprobe "${MP_QUIET}" cifs

        if mount.cifs "${NFSROOT}" "${mountpoint}" "${CIFSOPTS}" ; then
            rc=0
        fi
    fi
    return ${rc}
}

do_snap_copy ()
{
    fromdev="${1}"
    todir="${2}"
    snap_type="${3}"

    size=$(fs_size "${fromdev}" "" "used")

    if [ -b "${fromdev}" ]; then
        # look for free mem
        if [ -n "${HOMEMOUNTED}" -a "${snap_type}" = "HOME" ]; then
            todev=$(cat /proc/mounts | grep -s " $(base_path ${todir}) " | awk '{print $1}' )
            freespace=$(df -k  | grep -s ${todev} | awk '{print $4}')
        else
            freespace=$( expr $(awk '/MemFree/{print $2}' /proc/meminfo) + $( cat /proc/meminfo | grep Cached | head -n 1 | awk '/Cached/{print $2}' - ))
        fi

        tomount="/mnt/tmpsnap"
        if [ ! -d "${tomount}" ] ; then
            mkdir -p "${tomount}"
        fi

        fstype=$(get_fstype "${fromdev}")
        if [ -n "${fstype}" ]; then
            # Copying stuff...
            mount -t "${fstype}" -o ro,noatime "${fromdev}" "${tomount}"
            cp -a "${tomount}"/* ${todir}
            umount "${tomount}"
        else
            log_warning_msg "Unrecognized fstype: ${fstype} on ${fromdev}:${snap_type}"
        fi

        rmdir "${tomount}"
        if echo ${fromdev} | grep -qs loop; then
           losetup -d "${fromdev}"
        fi
        return 0
    else
        return 1
        [ "$quiet" != "y" ] && log_warning_msg "Unable to find the snapshot ${snap_type} medium"
    fi
}

try_snap ()
{
    # Look for $snap_label.* in block devices and copy the contents to $snap_mount
    #   and remember the device and filename for resync on exit in casper.init

    snap_label="${1}"
    snap_mount="${2}"
    snap_type="${3}"

    snapdata=$(find_files "${snap_label}.squashfs ${snap_label}.cpio.gz ${snap_label}.ext2")
    if [ ! -z "${snapdata}" ]; then
        snapdev="$(echo ${snapdata} | cut -f1 -d ' ')"
        snapback="$(echo ${snapdata} | cut -f2 -d ' ')"
        snapfile="$(echo ${snapdata} | cut -f3 -d ' ')"
        if echo "${snapfile}" | grep -qs '\(squashfs\|ext2\)'; then
            # squashfs or ext2 snapshot
            dev=$(get_backing_device "${snapback}/${snapfile}")
            if ! do_snap_copy "${dev}" "${snap_mount}" "${snap_type}"; then
                 log_warning_msg "Impossible to include the ${snapfile} Snapshot"
                 return 1
            fi
        else
            # cpio.gz snapshot
            if ! (cd "${snap_mount}" && zcat "${snapback}/${snapfile}" | cpio -i -u -d 2>/dev/null) ; then
                log_warning_msg "Impossible to include the ${snapfile} Snapshot"
                return 1
            fi
        fi
        umount "${snapback}"
    else
        dev=$(find_cow_device "${snap_label}")
        if [ -b ${dev} ]; then
            if echo "${dev}" | grep -qs loop; then
                # strange things happens, user confused?
                snaploop=$( losetup ${dev} | awk '{print $3}' | tr -d '()' )
                snapfile=$(basename ${snaploop})
                snapdev=$(cat /proc/mounts | awk '{print $2,$1}' | grep -es "^$( dirname ${snaploop} )" | cut -f2 -d ' ')
            else
                snapdev="${dev}"
            fi
            if ! do_snap_copy "${dev}" "${snap_mount}" "${snap_type}" ; then
                log_warning_msg "Impossible to include the ${snap_label} Snapshot"
                return 1
            else
                if [ -n "${snapfile}" ]; then
                     # it was a loop device, user confused
                     umount ${snapdev}
                fi
            fi
        else
            log_warning_msg "Impossible to include the ${snap_label} Snapshot"
            return 1
        fi
    fi
    echo "export ${snap_type}SNAP="${snap_mount}":${snapdev}:${snapfile}" >> /etc/casper.conf # for resync on reboot/halt
    return 0
}

setup_unionfs() {
    image_directory="$1"
    rootmnt="$2"

    modprobe "${MP_QUIET}" -b ${UNIONFS}

    # run-init can't deal with images in a subdir, but we're going to
    # move all of these away before it runs anyway.  No, we're not,
    # put them in / since move-mounting them into / breaks mono and
    # some other apps.

    croot="/"

    # Let's just mount the read-only file systems first
    rofsstring=""
    rofslist=""
    if [ "${NETBOOT}" = "nfs" ] ; then
        roopt="nfsro" # go aroung a bug in nfs-unionfs locking
    elif [ "${UNIONFS}" = "aufs" ]; then
        roopt="rr"
    else
        roopt="ro"
    fi

    mkdir -p "${croot}"
    for image_type in "ext2" "squashfs" "dir" ; do
        for image in "${image_directory}"/*."${image_type}"; do
            imagename=$(basename "${image}")
            if [ -d "${image}" ]; then
                # it is a plain directory: do nothing
                rofsstring="${image}=${roopt}:${rofsstring}"
                rofslist="${image} ${rofslist}"
            elif [ -f "${image}" ]; then
                backdev=$(get_backing_device "$image")
                fstype=$(get_fstype "${backdev}")
                if [ "${fstype}" = "unknown" ]; then
                    panic "Unknown file system type on ${backdev} (${image})"
                fi
                mkdir -p "${croot}/${imagename}"
                mount -t "${fstype}" -o ro,noatime "${backdev}" "${croot}/${imagename}" || panic "Can not mount $backdev ($image) on ${croot}/${imagename}" && rofsstring="${croot}/${imagename}=${roopt}:${rofsstring}" && rofslist="${croot}/${imagename} ${rofslist}"
            fi
        done
    done
    rofsstring=${rofsstring%:}

    mkdir -p /cow
    cowdevice="tmpfs"
    cow_fstype="tmpfs"

    # Looking for "${root_persistence}" device or file
    if [ -n "${PERSISTENT}" ]; then
        cowprobe=$(find_cow_device "${root_persistence}")
        if [ -b "${cowprobe}" ]; then
            cowdevice=${cowprobe}
            cow_fstype=$(get_fstype "${cowprobe}")
        else
            [ "$quiet" != "y" ] && log_warning_msg "Unable to find the persistent medium"
        fi
    fi

    mount ${cowdevice} -t ${cow_fstype} -o rw,noatime /cow || panic "Can not mount $cowdevice on /cow"

    mount -t ${UNIONFS} -o noatime,dirs=/cow=rw:$rofsstring ${UNIONFS} "$rootmnt" || panic "${UNIONFS} mount failed"

    # Adding other custom mounts
    if [ -n "${PERSISTENT}" ]; then
        # directly mount /home
        # FIXME: add a custom mounts configurable system
        homecow=$(find_cow_device "${home_persistence}" )
        if [ -b "${homecow}" ]; then
            mount -t $(get_fstype "${homecow}") -o rw,noatime,noexec "${homecow}" "${rootmnt}/home"
            export HOMEMOUNTED=1 # used to proper calculate free space in do_snap_copy()
        else
            [ "$quiet" != "y" ] && log_warning_msg "Unable to find the persistent home medium"
        fi
        # Look for other snapshots to copy in
        try_snap "${root_snapshot_label}" "${rootmnt}" "ROOT"
        try_snap "${home_snapshot_label}" "${rootmnt}/home" "HOME"
    fi

    if [ -n "${SHOWMOUNTS}" ]; then
        for d in ${rofslist}; do
            mkdir -p "${rootmnt}/casper/${d##*/}"
            case d in
                *.dir) # do nothing # mount -o bind "${d}" "${rootmnt}/casper/${d##*/}"
                    ;;
                *) mount -o move "${d}" "${rootmnt}/casper/${d##*/}"
                    ;;
            esac
        done
        # shows cow fs on /cow for use by casper-snapshot
        mkdir -p "${rootmnt}/cow"
        mount -o bind /cow "${rootmnt}/cow"
    fi

    # move the first mount; no head in busybox-initramfs
    for d in $(mount -t squashfs | cut -d\  -f 3); do
        mkdir -p "${rootmnt}/rofs"
        mount -o move "${d}" "${rootmnt}/rofs"
        break
    done
}

check_dev ()
{
    sysdev="${1}"
    devname="${2}"
    skip_uuid_check="${3}"
    if [ -z "${devname}" ]; then
        devname=$(sys2dev "${sysdev}")
    fi

    if [ -n "${LIVEMEDIA_OFFSET}" ]; then
        loopdevname=$(setup_loop "${devname}" "loop" "/sys/block/loop*" "${LIVEMEDIA_OFFSET}")
        devname="${loopdevname}" 
    fi

    fstype=$(get_fstype "${devname}")
    if is_supported_fs ${fstype}; then
        mount -t ${fstype} -o ro,noatime "${devname}" $mountpoint || continue
        if is_casper_path $mountpoint && \
           ([ "$skip_uuid_check" ] || matches_uuid $mountpoint); then
            echo $mountpoint
            return 0
        else
            umount $mountpoint
        fi
    fi

    if [ -n "${LIVEMEDIA_OFFSET}" ]; then
        losetup -d "${loopdevname}"
    fi
    return 1
}

find_livefs() {
    timeout="${1}"
    # first look at the one specified in the command line
    if [ ! -z "${LIVEMEDIA}" ]; then
        if check_dev "null" "${LIVEMEDIA}" "skip_uuid_check"; then
            return 0
        fi
    fi
    # don't start autodetection before timeout has expired
    if [ -n "${LIVEMEDIA_TIMEOUT}" ]; then
        if [ "${timeout}" -lt "${LIVEMEDIA_TIMEOUT}" ]; then
            return 1
        fi
    fi
    # or do the scan of block devices
    for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop | grep -v ram); do
        devname=$(sys2dev "${sysblock}")
        fstype=$(get_fstype "${devname}")
        if /lib/udev/cdrom_id ${devname} > /dev/null; then
            if check_dev "null" "${devname}" ; then
                return 0
            fi
        elif is_nice_device "${sysblock}" ; then
            for dev in $(subdevices "${sysblock}"); do
                if check_dev "${dev}" ; then
                    return 0
                fi
            done
        elif [ "${fstype}" = "squashfs" -o \
                "${fstype}" = "ext3" -o \
                "${fstype}" = "ext2" ]; then
            # This is an ugly hack situation, the block device has
            # an image directly on it.  It's hopefully
            # casper, so take it and run with it.
            ln -s "${devname}" "${devname}.${fstype}"
            echo "${devname}.${fstype}"
            return 0
        fi
    done
    return 1
}

set_usplash_timeout() {
    if [ -x /sbin/usplash_write ]; then
        /sbin/usplash_write "TIMEOUT 120"
    fi
}

mountroot() {
    exec 6>&1
    exec 7>&2
    exec > casper.log
    exec 2>&1

    parse_cmdline

    set_usplash_timeout
    [ "$quiet" != "y" ] && log_begin_msg "Running /scripts/casper-premount"
    run_scripts /scripts/casper-premount
    [ "$quiet" != "y" ] && log_end_msg

    # Needed here too because some things (*cough* udev *cough*)
    # changes the timeout

    set_usplash_timeout

    if [ ! -z "${NETBOOT}" ]; then
        if do_netmount ; then
            livefs_root="${mountpoint}"
        else
            panic "Unable to find a live file system on the network"
        fi
    else
        # Scan local devices for the image
        for i in 0 1 2 3 4 5 6 7 8 9 a b c d e f 10 11 12 13; do
            livefs_root=$(find_livefs $i)
            if [ "${livefs_root}" ]; then
                break
            fi
            sleep 1
        done
    fi

    if [ -z "${livefs_root}" ]; then
        panic "Unable to find a medium containing a live file system"
    fi

    if [ "${TORAM}" ]; then
        live_dest="ram"
    elif [ "${TODISK}" ]; then
        live_dest="${TODISK}"
    fi
    if [ "${live_dest}" ]; then
        log_begin_msg "Copying live_media to ${live_dest}"
        copy_live_to "${livefs_root}" "${live_dest}"
        log_end_msg
    fi

    mount_images_in_directory "${livefs_root}" "${rootmnt}"

    log_end_msg

    maybe_break casper-bottom
    [ "$quiet" != "y" ] && log_begin_msg "Running /scripts/casper-bottom"

    run_scripts /scripts/casper-bottom
    [ "$quiet" != "y" ] && log_end_msg

    exec 1>&6 6>&-
    exec 2>&7 7>&-
    cp casper.log "${rootmnt}/var/log/"
}
